Operation of regenerative ovens



C. OTTO OPERATION OF REGENERATIVE OVENS Feb. 15, 19,38.

F'ild July 28, 1936 2 Sheets-Sheet l INVENTOR adw zb- 8% ATTORNEY F 15,1938. c. OTTO OPERATION OF REGENERATIVE OVENS Filed July 28, 1936 2Sheets-Sheet 2 Fig. 5

Fig. 4

INVENTOR 5 ATTORNEY ovens adapted to be heated Patented Feb. 15, 1938PATENT OFFICE 2,108,610 OPERATION OF REGENERATIVE OVENS Carl Otto,Essen, Germany Application July 28, 1936, Serial No.

In Germany May 17, 1935 3 Claims.

The present invention relates to industrial by rich gas and providedwith means for pre-heating the air of combustion by regenerators, inparticular under- 'fired ovens.

In rich gas-heated ovens in which the air of combustion is pre-heated bymeans of regenerators frequently explosions occur if the place where therich gas is shut on and the place yvhere the gas is exist between thesetwo places, which explosions are due to the feature that the airentering said spaces or intentionally supplied to them fordegraphitizing purposes, is'mixed therein with the remainder of'the richgas so as to form an explosive mixture. In order to obviate thisdrawback and to remove upon reversal of the draught the unburned gasremainder from the shut-off gas distributing pipes of regenerative ovensintended for the production of gas and coke, one

has already 'connected the gas distributing pipes 7 after the gas feedhas been shut off, that is, while they communicate in known manner withthe outer air, to the waste heat flue fora short period of time, say oneminute, by special connecting pipes fitted with valves. In this way therich gas still existing in the space between the shutoff valve and theburning place is sucked into the waste heat flue by the pressure belowatmospheric prevailing in this flue.

This mode of operation, however, suffers from the drawback that unburnedrich gas arrives in the waste heat flue where, if the waste gases contain air, it may cause explosions. In addition, a rather largequantityof rich gas gets lost thereby. I The invention has now for itsobject to obviate this drawback which object is achieved by inert gasesbeing blown for some time into the rich.

gas feed pipes, after the gas feed has been shut off. This operation maytake place immediately before the commencement of the gas feed. Inertgases suited for this purpose are for example the waste gases of theoven or steam. The period of time required for blowing-in the inert gasis short when compared with the total duration of the regeneration, itmay amount to about one minute.

In. order that the invention may be clearly understood and readilycarried into effect, a preferred embodiment of the means for blowing-inthe inert gas is illustrated by way of example in the accompanyingdrawings as applied to an underfired coke oven. Inthese drawings Figure1 shows part of the arched foundation burned are far distant fromoneanother and spaces of larger cross sectional area 'izontal rich gasdistributing The three way cocks g of the oven with the lower portion ofthe regenerator spaces, and is a section on line 1-1 of'Figure 2,

Figure 2 is a vertical section on line 11-11 of Figure 1 the right handportion of the figure being seen from the left of said line, and theleft hand portion of the figure being seen from the right of said line,

Figure 3 is an elevation of the oven parts situated below the sectionline III-III of Figure 2,

Figure 4 is a detail of Figure 1 in a somewhat modified form and onlarger scale, and

Figure 5 shows the same details in a view corresponding to Figure 2.

In the underflred oven illustrated in these figures the stack flue acommunicates with a suction blower b driven by a motor 0 which isstarted by the reversing winch (by any suitable way cocks g, pipes p,and the rich gas valves h, which likewise are three way cocks, into thehorizontal rich gas distributing branches m. The rich gas is suppliedthrough a channel It and the ascending pipes 0 through each two rich gasvalves h either the upper or lower of which is opened in everyregeneration period, into the'hormains m from which vertical pipes 12are branched off. The oven illustrated is constructed with hair-pinflues, so that the even-numbered pipes n are connected to one main m andthe odd-numbered pipes to the other main The valves h thus communicatewith the ascending pipes o as well as with a main m and with the pipes12. The three way cock 9 communicates with the pipes 12 and with thewaste heat distributing pipe I and have further each an inlet port q forthe degraphitizing air.

Upon reversal of the flow the following operations take place: First theblower b is actuated to establish, and thereafter to maintain, a certainpressure in the waste heat distributing pipe f. are then turned over soas to connect the pipes p withthe distributing pipe f. Next each of thecocks h which till now has fed the rich gas is turned degrees so thatwaste heat from the waste heat distributing pipe 1 flows into themain-m,till now filled with rich gas, and into the rich gas branches nconnected thereto, the waste heat pushing away the rich gas stillexheating flues. Simultaneously also waste heat passes through the othervalve h of the same pair of valves into the main m which did not leadgas during the preceding regeneration period and pushes out the'airpreviously held in the last mentioned pipes m and their branches n. Thebattery waste heat valves are turned over whereby the direction of flowin the heating. flues is changed. Thereuponthe main m till now not fedwith gas is adjusted to gas feed by turning over the respective valve h,whereby the next regeneration period is started. The time elapsingbetween turning over' the two rich gas valves It will in general besumcient to push away by the following waste heat the gas still presentin the distributing pipes. Therefore, simultaneously with the initiationof the new regeneration period,-the appropriate three way cocks y can beturned into the positions in which their air inlet ports q are open forthe passage of degraphitizing air into the rich gas mains m'which arenot then feeding rich gas. Degraphitizing air may thus be suppliedduring the first section thereof,

for example for 10 minutes, with a total duration of the regenerationperiod of 30 minutes.

In the modification illustrated in Figures 4 and 5 the three way cook ais ,replaced by a simple shut-off valve 1' which in general ispermanently open and is closed only when the heating wall situated abovethe respective pipe 17 is to be put out of operation. In thisarrangement further the pipes p have trumpet-like enlarged ends 3 whichopen at a'certain distance apart from the air ports of the rich gasvalves h. The: arrangement of the suction blower b and of the remainingmembers serving to blow-in the waste heat may be the same as in thefirst embodiment. The waste gases are pressed into the pipes i also inthis embodiment from the beginning of the reversal or shortly before andup till the re-- versal is terminated. The trumpet ends s facing the airports t are soshaped and the pressure prevailing in the distributingpipe I is so selected,

that only waste gas enters the air ports ofthe valves h and pushes awaythe remainders of rich gas still present in the gas main m previouslyfed with gas.

What I claim and desire to secure by Letters Patent is:-

1. In the operation of a regeneratiVe furnace comprising a connectionoperable to'alternately supply rich fuel gas and degraphitizing airduring successive regeneration periods, the method which consists inpassing an inert gas-through said connection during intervals prior toand following the passage of degraphitizing air through said connection.

2. In the operation of a regenerative oven furnace having two sets ofrich fuel gas supply connections, each set supplying rich fuel gasduring periods alternating with periods in which rich fuel gas issupplied by the other set, the method which consists in passing inertgas, degraphitizing air and inert gas successively through said supplyconnections during a period in which the connections are notsupplyingfuel gas.

3. In the operation of a regenerative coke oven battery having a stackflue drawing waste 7 gases away from the battery and having two .sets

of rich fuel gas supply connections, each connection adapted to have itsinlet portion opened to the atmosphere, each set supplying rich fuelgasduring periods alternating with the periods in which rich fuel gas issupplied by the other set, the method which consists in opening theinlet portionof each supply connection to the atmosphere so thatatmospheric air may be drawn through the connection during periodsalternating with periods in which rich fuel gas is supplied through saidconnection, and compressing waste gases withdrawn from the battery andpassing a portion of said gases through each connection during a briefperiod intervening between each period during which rich fuel gas issupplied through said connection and the immediately following andimmediately preceding periods during which the inlet portion of theconnection is open to the atmosphere, whereby waste gases,degraphitizing air and waste gases are passed successively through eachconnection during each period in which said connection is not supplyingfuel gas.

CARL O'I'I'O.

